Cryosurgical fluid control system



Dec. E, 1966 .J. L. SHEPHERD 37 A CRYOSURGICAL FLUID CONTROL SYSTEM Filed July 1, 1965 2 Sheets-Sheet l INVENTOR. JBM L. SHEPHERQ ATTORNEY Dec. 6, 1966 J. L. SHEPHERD CRYOSURGIGAL FLUID CONTROL SYSTEM 2 Sheets-Sheet Filed July 1, 1965 INVENTORA JIM L. SHEPHERD ATTORNEY United States Patent 3,289,424 CRYOSURGICAL FLUID CONTROL SYSTEM Jim Lee Shepherd, Indianapolis, Ind., assignor to Union Carbide Corporation, a corporation of New York Filed July 1, 1963, Ser. No. 291,876 Claims. (Cl. 6255) This invention relates to cryogenic liquid cooling systems. More particularly, this invention relates to the control of cryosurgery systems for cooling localized areas of the human body.

A primary object of the present invention is to provide a cryogenic liquid cooling system for cooling localized areas of the human body. Another object is to provide a cryogenic liquid cooling system wherein the flow of cryogenic liquid in heat exchange with a remotely-located object is controlled by controllably venting such cryogenic liquid. A further object of the present invention is to provide a system for controlling the flow of a cryogenic liquid. These and other objects and advantages of the present invention are described hereinafter in conjunction with the drawings wherein:

FIGURES 1, 1a and lb are schematic flow diagrams illustrating features of the present invention;

FIGURE 2 is an elevational view, partially in crosssection, of a surgical system embodying features of the present invention; and

FIGURES 3-5 are views which illustrate other features of the present invention.

Inasmuch as cryogenic liquids are being increasingly used as refrigerating media in cryosurgery systems where the refrigerating effects of the liquids individually cool localized areas of the human body which are remotely located from the cryogenic liquid supply means, the present invention is particularly suited for use in such cryosurgery systems. The cryogenic liquid cooling system of the present invention is also particularly suited for cooling an object such as an infrared detecting cell in the nose of a missile or some other electronic component requiring refrigeration from a remotely-located cryogenic liquid supply means.

The present invention comprises a system for cooling an object by heat exchange with cryogenic liquid supplied from a source thereof including cryogenic liquid storage means, heat exchange means, cryogenic liquid supply means joined to the heat exchange means and cryogenic liquid storage means, venting means communicating with the heat exchange means for venting fluid discharged into the heat exchange means, and cryogenic liquid flow control means connected to the cryogenic liquid storage means and the venting means and constructed and arranged to provide alternate fluid communication between the venting means and the vapor space of the cryogenic liquid storage means. and between the venting means and the surrounding atmosphere.

FIGURE 1 shows a cooling system where a cryogenic liquid is transferred from a storage means through a supply conduit 12 to a heat exchange means or zone 14 and is at least partially vaporized therein to provide a refrigerating medium for an object 16 which is remotelylocated from the storage means 10. In such a cooling system, it is frequently necessary to terminate liquid flow substantially instantaneously to prevent the temperature of the object 16 from falling below a particular level. The present invention provides a flow control means 18 that communicates with the heat exchange means or zone 14 through vent conduit 20 and with the vapor space of storage means 10 through a conduit 22. During operation of the cooling system shown in FIGURE 1, the cryogenic liquid conducted and at least partially vaporized in heat exchange with the object 16 is vented through vent con- 3,289,424 Patented Dec. 6, 1966 duit 20 and flow control means 18 to the atmosphere through conduit 24. To terminate the flow of cryogenic liquid, flow control means 18 closes conduit 24 to the venting fluid and opens conduit 22 thereto. Consequently, the pressure within vent conduit 20 is equalized with the pressure within supply conduit 12 and the fluid flow throrghout the system is substantially immediately terminate FIGURE 1a shows a modification of the flow control means 18 of FIGURE 1 wherein a flow control means 18a is placed in the atmospheric vent conduit 24 and a flow control means 18b is placed in the storage means conduit 22. These two means are connected such that when one is open, the other is closed to provide the alternate fluid communication between the vent conduit 20 and the vapor space of the storage means 20 through conduit 22 and between the vent conduit 20 and the surrounding atmosphere through conduit 24 as described above. Flow control means 18 or 18a and 18b may be valve means of the on-oif type and may be manually or automatically operable.

FIGURE 1b shows a further modification of the flow control means 18 of FIGURE 1 wherein an exhaust control means is placed in the atmospheric vent conduit 24. This exhaust control means 180, in its simplest form, comprises a small diameter orifice 18d and a larger diameter by-pass line 18c. During normal operation of the FIGURE 1 system, vapor would be vented through flow control means 18 and the orifice 18a. of exhaust control means 180 of FIGURE 16. If vapor must be vented more rapidly so as to increase the flow cryogenic liquid to zone 14, exhaust control means 180 will switch the venting vapor into larger diameter by-pass line 18c, either manually or automatically. The exhaust control feature of 18c may be incorporated into the flow control means 18 if desired thereby combining the flow control feature of the present invention with the variable control over the venting vapor in one device.

FIGURE 2 shows a preferred embodiment of the present invention comprising a cryosurgery system of the type described above. This embodiment comprises a cryogenic liquid storage means 10, a transfer conduit 26, and a surgical cannula 28. Storage means 10 is preferably a double-walled, vacuum-insulated container which permits storing a cyrogenic liquid for a considerable period. Transfer conduit 26 is preferably a double-walled vacuum-insulated hose which both incorporates cryogenic liquid supply conduit 12 and provides the function of vent conduit 28 of FIGURE l to facilitate using the system. Surgical cannula 28 provides the function of heat exchange means or zone 14 of FIGURE 1 when positioned adjacent to an are-a of the body to be cooled. Transfer conduit 26 is attached to storage means 10 by a connecting means 30 which provides fluid communication with transfer conduit 26, storage means 10 and flow control means 32. Flow control means 32 may be similar to the valve means depicted in FIGURE 1, FIGURE 1a, or FIG- URE 1b. As shown in FIGURE 2, the transfer conduit 26 comprises two sets of currugated, or bellows tubes; the smaller set connecting to the surgical cannula 28 and the larger set connecting to the flow control means 32. The smaller set is very flexible to provide a maximum degree of surgical cannula movement.

Cryogenic liquid supply conduit 12 extends from the bottom of storage means 10 through connecting means 30 and transfer conduit 26 into surgical cannula 28 to the tip thereof. Cryogenic liquid is transferred from storage means 10 through supply conduit 12 and discharged into the tip of surgical cannula 2'8, and is at least partially vaporized by heat conducted into the tip from the surrounding area, and then vented from surgical cannula 28 through the annulus between the inner surface of transfer conduit inner wall 26b and the outer surface of supply conduit 12 and through vent control means 32.

Surgical cannula 28 comprises a hollow thermally conductive tip member 34 and a double-walled vacuum insulated cannula conduit 36 consisting of concentric inner and outer tubes, 36a and 36b, respectively, with an evacuab'le insulating space 360 therebetween. The cannula conduit 36 is preferably joined to tip member 34 by means such as soldering or brazing. Alternately, tip member 34 could be threaded and screwed on to the cannulaconduit 36 to permit the substitution of tip members having outer surface configurations other than the spherical surface shown. Although the spherical outer surface configuration of the tip member 34 is particularly desirable because it will cool a sphere of uniform diameter around it, other tip member shapes such as curved or flat spatular shapes or various curved shapes such as a corkscrew shape may be desirable to cool particular areas.

Because the tip member 34 is constructed of a highly thermally conductive material, such as silver or the like, the heat transferred from the surrounding area through the tip member 34 will meet virtually no thermal resistance and, consequently, the cooled area will tend to assume the shape of the tip member used. By constructing the cannula conduit 36 of concentric tubes 36a and 36b and evacuating the insulating space 360 .t-herebetween, the refrigerating effects of the cryogenic liquid discharged into tip member 34 are confined to the outer surface of tip member 34 thereby providing greater control over such refrigerating effects. To transfer as much of the refrigerating effects of the cryogenic liquid through tip member 34 as possible, the interior of tip member 34 may be formed by various methods designed to increase heat transfer; a preferred method being to bore a solid tip member and thread the bored interior to produce heat transfer fins. With a suitable tip member construction, substantially all of the cryogenic liquid transferred into the tip member interior can be vaporized and vented as vapor from the surgical cannula 28 through either the annulus between the inner surface tube 36b and the outer surface of supply conduit 12 as shown in FIGURE 2 or a separate venting conduit 38 as shown in FIGURE 3.

Surgical cannula 28 can be either integrally joined to the transfer conduit 26 or joined as shown in FIGURE 4 such that it may be detached and another surgical cannula substituted therefor. As shown in FIGURE 4, surgical cannula 28 may be joined to transfer conduit 26 by means of a coupler 40 comprising a nut which engages a threaded section of surgical cannula 28. In this embodiment, surgical cannula 28 may be provided with a venting connection 42 which is joined to a vent conduit such as vent conduit 20 of FIGURE 1 connecting to flow control means 18. Alternately, the interior of tube. 36b of the cannula conduit may be constructed to be communicable with the interior of transfer conduit 26 when the surgical cannula 28 and the transfer conduit 26 are connected thereby providing a continuous venting space for the vapor from the tip member 34 of surgical cannula 28 to the flow control means 18.

Transfer conduit 26 comprises concentric corrugated inner and outer tubes 26a and 26b respectively, with an evacuable insulating space 26c therebetween. The annulus between the inner surface of tube 26b and the outer surface of supply conduit 12 communicates with the flow controlling means 18 and a similar annulus in surgical cannula 28 for the venting of vapor from the tip mem- 'ber 34 of surgical cannula 28. By providing this annular space for the venting of vapor, a separate vent conduit such as vent conduit 20 of FIGURE 1 is not required.

The section of cryogenic liquid supply conduit 12 extending into the supply means is preferably partially enclosed by a vacuum conduit 48 that is evacuated and filled with a gas adsorbent material 50 as shown in FIG- URE 5. This gas adsorbent material is preferably provided in gaseous communication with the evacuable insulating space 260 and 360 of transfer conduit 26 and surgical cannula 34, respectively, to maintain the vacuum therein. Alternately, transfer conduit 26, surgical cannula 34, or both, may be provided with independent vacuum maintaining means in which case the detachment of one of these elements from the systems would not disrupt the vacuum in the other elements.

Cryogenic liquid supply means 10 is filled with cryogenic liquid through the top. Cryogenic liquid supply conduit 12 is then inserted into supply means 10 and connecting means 30 is attached to the top of supply means 10. Means within cryogenic liquid supply means 10 then pressurize the cryogenic liquid stored therein for transfer to surgical cannula 28 on demand.

The temperature of tip member 34 may be manually controlled by regulating the pressure within the venting space and thereby controlling cryogenic liquid flow from cryogenic liquid supply conduit 12 into the hollow interior of surgical cannula 34. The tip member temperature is monitored by a thermocouple (not shown) at the end thereof and the cryogenic liquid flow controlled in response to this monitored temperature.

To cool the tip member 34, flow control means 32 interrupts the fluid communication between the vapor venting space and the vapor space of supply means 10 and opens the vapor venting space of transfer conduit 26 to the atmosphere through vapor vent 54. The pressure differ ential between the atmosphere and the cryogenic fluid in supply means It) is then available as the driving force to transfer cryogenic liquid into thesurgical cannula 28.

Although particular preferred embodiments of the present invention have been described in detail, it is to be understood that certain features may be used without others or modified and still be Within the scope of the present invention.

What is claimed is:

1. In a system for controlled freezing of tissue in indirect heat exchange with a cryogenic liquid supplied from a source thereof including apparatus comprising cryogenic liquid storage means, a surgical cannula, having a fluid inlet and a fluid outlet, and cryogenic liquid supply means joined to said inlet to said surgical cannula and to said cryogenic liquid storage means, and venting means communicating with said outlet to said surgical cannula to vent vapor therefrom; the combination with such apparatus of cryogenic liquid flow control means connected to said cryogenic liquid storage means and said venting means downstream from the surgical cannula outlet, and constructed and arranged to provide alternate fluid communication between said venting means and the vapor space of said cryogenic liquid storage means and between said venting means and the surrounding atmosphere such that the flow of cryogenic liquid in the freezing system may be terminated by communicating said venting means with said vapor space.

2. In a system for controlled freezing of tissue in indirect heat exchange wit-h a cryogenic liquid supplied from a source thereof including apparatus comprising cryogenic liquid storage means, a surgical cannula, a transfer conduit joined to said surgical cannula and said cryogenic liquid storage means, and a cryogenic liquid supply conduit extending from said cryogenic liquid storage means through said transfer conduit into said surgical cannula, with a venting space being provided between said cryogenic liquid supply conduit and the interior of said surgical cannula and between said cryogenic liquid supply conduit and the interior of said transfer conduit for fluid discharged into said surgical cannula; the combination with such apparatus of cryogenic liquid flow control means connected to said cryogenic liquid storage means and said transfer conduit, and constructed and arranged to provide alternate fluid communication between the venting space of said transfer conduit and the vapor space of said cryogenic liquid storage means and between the venting space of said transfer conduit and the surrounding atmosphere such that the flow of cryogenic liquid in the freezing system. may be terminated by communicating said venting space with said vapor space.

3. In a system for controlled freezing of tissue in indirect heat exchange with a cryogenic liquid supplied from a source thereof including apparatus comprising cryogenic liquid storage means, a surgical cannula having a thermally conductive hollow tip member and a cannula conduit joined to the tip member including inner and outer tubes with an evacuable insulating space therebetween, a transfer conduit joined to said surgical cannula having inner and outer tubes with an evacuable insulating space therebetween and means for connecting said transfer conduit to said cryogenic liquid storage means, and a cryogenic liquid supply conduit communicable with said cryogenic liquid storage means and extending through the inner tube of said transfer conduit and the inner tube of said surgical cannula and terminating within said tip member, with a venting space being provided between said cryogenic liquid supply conduit and the interior of said surgical cannula and between said cryogenic liquid supply conduit and the interior of said transfer conduit for fluid discharged into said tip member; the combination with such apparatus of cryogenic liquid flow control means connected to said cryogenic liquid storage means and said transfer conduit, and constructed and arranged to provide alternate fluid communication between the venting space of said transfer conduit and the vapor space of said cryogenic liquid storage means and between the venting space of said transfer conduit and the surrounding atmosphere such that the flow of cryogenic liquid in the freezing system may be terminated by communicating said venting space with said vapor space.

4. A cryogenic liquid cooling system comprising cryogenic liquid storage means, heat exchange means having a fluid inlet and a fluid outlet for cooling an object remotely-located from said cryogenic liquid storage means, cryogenic liquid supply means joined to said inlet to said heat exchange means and to said cryogenic liquid storage means, venting means communicating with said outlet to said heat exchange means, and cryogenic liquid flow control means connected to said cryogenic liquid storage means and to said venting means downstream from the heat exchange means outlet and constructed and arranged to provide alternate fluid communication between said venting means and the vapor space of said cryogenic liquid storage means and between said venting means and the surrounding atmosphere such that the flow of cryogenic liquid in the cooling system may be terminated by communicating said venting means with said vapor space.

5. A cryogenic liquid cooling system comprising cryogenic liquid storage means, heat exchange means having a fluid inlet and a fluid outlet for cooling an object remotelydocated from said cryogenic liquid storage means, a cryogenic liquid supply conduit joined to said inlet to said heat exchange means and to said cryogenic liquid storage means, a vent conduit joined to said outlet to said heat exchange means, and cryogenic liquid flow control means connected to said cryogenic liquid storage means and said vent conduit downstream from the heat exchange means outlet and constructed and arranged to provide alternate fluid communication between said vent conduit and the vapor space of said cryogenic liquid storage means and between said vent conduit and the surrounding atmosphere such that the flow of cryogenic liquid in the cooling system may be substantially instantaneously terminated by communicating said vent conduit with said vapor space.

References Cited by the Examiner UNITED STATES PATENTS 1,780,267 11/ 1930 Malone 6262 2,943,454 7/ 1960 Lewis 6252 2,943,459 7/1960 Rind 62-217 2,958,204 11/1960 Spaulding 6252 MEYER PERLIN, Primary Examiner. ROBERT A. OLEARY, Examiner. 

1. IN A SYSTEM FOR CONTROLLED FREEZING TO TISSUE IN INDIRECT HEAT EXCHANGE WITH A CRYOGENIC LIQUID SUPPLIED FROM A SOURCE THEREOF INCLUDING APPARATUS COMPRISING CRYOGENIC LIQUID STORAGE MEANS, A SURGICAL CANNULA, HAVING A FLUID INLET AND A FLUID OUTLET, AND CRYOGENIC LIQUID SUPPLY MEANS JOINED TO SAID INLET TO SAID SURGICAL CANNULA AND TO SAID CRYOGENIC LIQUID STORAGE MEANS, AND VENTING MEANS COMMUNICATING WITH SAID OUTLET TO SAID SURGICAL CANNULA TO VENT VAPOR THEREFROM; THE COMBINATION WITH SUCH APPARATUS TO CRYOGNEIC LIQUID FLUID FLOW CONTROL MEANS CONNECTED TO SAID CRYOGENIC LIQUID STORAGE MEANS AND SAID VENTING MEANS DOWNSTREAM FROM THE SURGICAL CANNULA OUTLET, AND CONSTRUCTED AND ARRANGED TO PROVIDE ALTERNATE FLUID COMMUNICATION BETWEEN SAID VENTING MEANS AND THE VAPOR SPACE OF SAID CRYOGENIC LIQUID STORAGE MEANS AND BETWEEN SAID VENTING MEANS AND THE SURROUNDING ATMOSPHERE SUCH THAT THE FLOW OF CRYOGENIC LIQUID IN THE FREEZING SYSTEM MAY BE TERMINATED BY COMMUNICATING SAID VENTING MEANS WITH SAID VAPOR SPACE. 